1. Field of the Invention
This invention relates to a horn means for an automotive vehicle, and more particularly to the horn means which comprises a highly reliable horn switch assembly.
2. Description of the Prior Art
In a conventional horn means for an automotive vehicle, a horn switch is generally provided on a pad portion in the steering wheel structure, while a horn which generates a warning sound is provided on a vehicle body. Each of FIGS. 17 and 18 of the drawings shows a block diagram of the conventional horn means. The horn means shown in FIG. 17 comprises a horn switch 1 one end of which is earthed to the vehicle body through a handle shaft, a horn 3 one end of which is connected to a high level power source Vcc, a contact ring means 2 having a contact ring 21 connected to the other end of the horn switch and a contact pin 26 connected to the other end of the horn 3. The electric current of several hundreds mA flows from the source Vcc to the earth through the horn 3, the contact ring means 2 and the horn switch 1.
In the horn means shown in FIG. 18, a relay 4 is provided between the contact pin 26 and the high level power source Vcc. The horn 3 is actuated by a normally OFF contact point 41 of the relay 4. In case of this known art, an electric current of several hundreds mA flows between the horn switch 1 and the contact ring 21. That is, according to these prior arts, in either case, the horn switch 1 is arranged to actuate the horn 3 through the contact ring 21.
According to the experiments, these conventional horn means have the following drawbacks. When a membrane switch having a high on-state resistance was used as the horn switch 1, it has been observed that a voltage drop was produced, by which the relay 4 often became inoperative or the sound of the horn 3 too low. Also, when a diaphragm switch which has a very low on-state resistance and current capacity was used, life of the contact point 41 was extremely shortened upon application of the current of several hundreds mA.